Abstract. Unusual aerosol enhancement is often observed at Syowa Station, Antarctica,
during winter and spring. Simultaneous aerosol measurements near the
surface and in the upper atmosphere were conducted twice using a ground-based
optical particle counter, a balloon-borne optical particle counter, and
micropulse lidar (MPL) in August and September 2012. During 13–15 August,
aerosol enhancement occurred immediately after a storm condition. A high
backscatter ratio and high aerosol concentrations were observed from the surface
to ca. 2.5 km over Syowa Station. Clouds appeared occasionally at the top of
the aerosol-enhanced layer during the episode. Aerosol enhancement was
terminated on 15 August by strong winds from a cyclone's approach. In the
second case, on 5–7 September, aerosol number concentrations in
Dp > 0.3 μm near the surface
reached > 104 L−1 at about 15:00 UT (Universal Time) on 5 September
despite calm wind conditions, whereas MPL measurement exhibited aerosols were
enhanced at about 04:00 UT at 1000–1500 m above Syowa Station. The aerosol
enhancement occurred near the surface to ca. 4 km. In both cases, air masses
with high aerosol enhancement below 2.5–3 km were transported mostly from
the boundary layer over the sea-ice area. In addition, air masses at 3–4 km
in the second case came from the boundary layer over the open-sea area. This
air mass history strongly suggests that dispersion of sea-salt particles from
the sea-ice surface contributes considerably to aerosol enhancement in the
lower free troposphere (about 3 km) and that the release of sea-salt
particles from the ocean surface engenders high aerosol concentrations in the
free troposphere (3–4 km). Continuous MPL measurements indicate that high
aerosol enhancement occurred mostly in surface–lower free troposphere
(3 km) during the period July–September.